1. Field of the Invention
The present invention relates in general to a shift control mechanism for an automotive manual transmission.
2. Description of the Prior Art
A known reverse shift mechanism consists of a reverse shift bracket, reverse fork lever, reverse shift arm and a reverse shift plate, which are joined to constitute a linkage as disclosed in Japanese Provisional Patent Publication No. 60-81541.
The reverse shift bracket is reciprocatively movable between a neutral position and a reverse shifting position in response to shift effort applied to a control lever. The reverse fork lever is engaged with a reverse idler gear and rotatable about a stationary pin for moving the reverse idler gear between a neutral position and a reverse shifting position. The reverse shift arm is adapted to receive shift effort from an input finger of the reverse shift bracket to rotate about a stationary pin. The reverse shift plate has an end rotatably connected at an end to the reverse shift arm by a movable pin and the other end connected to the reverse fork lever by a movable pin.
The prior reverse shift mechanism has a disadvantage that it is low in transmission efficiency and therefore requires relatively large shift effort, particularly at the instant meshing the reverse idler gear with the reverse main gear and the reverse input gear. This is because during movement of the revese shift bracket from the neutral position to the reverse shifting position, shift effort is transmitted from the input finger of the reverse shift bracket to the reverse shift arm and from which it is transmitted to the reverse fork lever through the reverse shift plate, whereby to move the reverse fork lever from the neutral position to the reverse shifting position.
In order to attain a higher transmission efficiency, it is readily considered to transmit shift effort from the reverse shift bracket to the reverse fork lever directly. This however causes another problem that the transmission is likely to slip out of reverse since the linkage cannot serve as means for preventing such slipping.